CN113135827B - Method for continuously and stably recycling aniline in aniline wastewater - Google Patents
Method for continuously and stably recycling aniline in aniline wastewater Download PDFInfo
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- CN113135827B CN113135827B CN202110473470.XA CN202110473470A CN113135827B CN 113135827 B CN113135827 B CN 113135827B CN 202110473470 A CN202110473470 A CN 202110473470A CN 113135827 B CN113135827 B CN 113135827B
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Abstract
The invention belongs to the technical field of preparation of organic chemical raw materials, and relates to a method for continuously and stably recycling aniline in aniline wastewater, which is characterized in that an aniline wastewater flow automatic control device is arranged on an aniline wastewater recycling pipeline to control the water content of aniline in crude aniline products entering an aniline refining system, and the aniline crude products enter the aniline refining system to prepare aniline pure products; the aniline wastewater flow control device comprises a conductivity meter. According to the invention, accurate recovery of aniline in the aniline wastewater is realized through the conductivity meter, the water content of aniline in the recovery process is reduced, and the influence on the operation condition of the aniline primary distillation tower caused by mixing of wastewater is avoided; the recovered aniline and the crude aniline obtained by separation enter an aniline primary distillation tower for refining, so that the aniline water content entering the primary distillation tower is ensured to be less than 2.0%, and the stable operation of an aniline refining system is ensured.
Description
Technical Field
The invention belongs to the technical field of preparation of organic chemical raw materials, and relates to a method for continuously and stably recycling aniline in aniline wastewater.
Background
Aniline is an important organic chemical raw material and chemical product, and is mainly used for producing MDI, rubber auxiliary agent, medicine, dye pigment, intermediate and the like.
Condensing and separating reactants obtained by preparing aniline by nitrobenzene gas phase hydrogenation to obtain aniline wastewater and benzeneThe difference of specific gravity between the aniline wastewater and the aniline crude product is small (aniline 1.02kg/m 3 The method comprises the steps of carrying out a first treatment on the surface of the Water 1.00kg/m 3 ) In the aniline waste water generated by physical separation, part of aniline can be entrained to enter an aniline waste water storage tank and continuously accumulate at the tank bottom, the aniline needs to be recovered once every 12 hours for recycling the part, and the aniline waste water directly enters an aniline primary distillation tower to carry out primary distillation operation, but the waste water in the aniline is inevitably brought into the aniline primary distillation tower in the recovery process, so that the operation parameters of the aniline primary distillation tower are severely fluctuated, a large amount of control indexes are subjected to standard removal alarm, the operation continuity and stability of an aniline refining system are seriously damaged, the low-boiling content in the aniline is increased, and the product quality is seriously influenced.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a method for continuously and stably recycling aniline in aniline wastewater, thereby ensuring the continuity and stability of the operation of an aniline refining system. And particularly, whether the aniline in the aniline wastewater is completely recovered or not is judged by reading of a conductivity meter in the recovery process, so that the purpose of continuously recovering the aniline in the aniline wastewater is realized.
The invention adopts the main technical scheme that: a method for continuously and stably recycling aniline in aniline wastewater is characterized in that an aniline wastewater flow automatic control device is arranged on an aniline wastewater recycling pipeline to control the water content of aniline in crude aniline products entering an aniline refining system, and the aniline crude products enter the aniline refining system to prepare aniline pure products; the aniline wastewater flow control device comprises a conductivity meter.
Generally, the method for continuously and stably recycling aniline in aniline wastewater mainly comprises an aniline wastewater tank, an aniline crude product tank and an aniline refining system, wherein an aniline wastewater flow automatic control device is arranged between the aniline wastewater tank and the aniline crude product tank.
The aniline wastewater flow control device comprises a centrifugal pump, an automatic regulating valve and a flowmeter, and a bypass of the automatic regulating valve is provided with a conductivity meter.
The flow range of the centrifugal pump is 0-10 m 3 /h。
The water content of the aniline in the crude aniline product entering the aniline refining system is controlled to be less than 2.0%.
The switch of the automatic regulating valve is controlled by a conductivity meter.
And when the display value of the conductivity meter is more than 0.02s/m, the automatic regulating valve is closed, and recovery is stopped.
The aniline refining system comprises an aniline primary distillation tower and an aniline rectification tower.
The primary distillation tower operating conditions: the temperature of the tower top is 100-135 ℃, the temperature of the tower bottom is 140-150 ℃, and the pressure of the tower top is 20-45 kPa (A); rectifying column operating conditions: the temperature of the tower top is 100-120 ℃, the temperature of the tower bottom is less than or equal to 115 ℃, and the pressure of the tower top is less than or equal to 15 kPa (A).
Compared with the prior art, the invention has the beneficial effects that:
(1) The aniline in the aniline wastewater is accurately recovered through the conductivity meter, the water content of the aniline in the recovery process is reduced, and the influence on the operation condition of the aniline primary distillation tower caused by the mixing of the wastewater is avoided;
(2) The recovered aniline and the crude aniline obtained by separation enter an aniline primary distillation tower for refining, so that the aniline water content entering the primary distillation tower is ensured to be less than 2.0%, and the stable operation of an aniline refining system is ensured.
Drawings
FIG. 1 is a schematic process flow diagram of an embodiment of the method of the present invention.
In the figure, a 1-aniline wastewater tank; 2-a valve I; 3-a centrifugal pump I; 4-an automatic regulating valve; 5-conductivity meter; 6-a flow meter; 7-aniline crude product tank; 8-valve II; 9-a centrifugal pump II; 10-aniline primary distillation tower; 11-aniline rectifying column.
Detailed Description
The process according to the invention is described in detail below with reference to examples and figures.
Examples
The method of the following example was used in the aniline production process by vapor phase hydrogenation of nitrobenzene.
The method for continuously and stably recovering the aniline in the aniline wastewater is shown in the accompanying figure 1, and the process flow mainly comprises an aniline wastewater tank 1, an aniline crude product tank 7 and an aniline refining system, wherein an aniline wastewater flow automatic control device is arranged between the aniline wastewater tank 1 and the aniline crude product tank 7.
In the embodiment, the aniline wastewater flow control device mainly comprises a centrifugal pump I, an automatic regulating valve 4 and a flowmeter 6, wherein a conductivity meter 5 is arranged on a bypass of the automatic regulating valve 4.
In the embodiment, the flow range of the centrifugal pump I is 0-10 m 3 /h; the water content of 7 aniline in the crude product tank is less than 2.0%; the automatic regulating valve 4 is controlled by the conductivity meter 5, and when the display value of the conductivity meter 5 is more than 0.02s/m, the automatic regulating valve 4 is closed to stop recovery.
In an embodiment, the aniline refining system includes an aniline primary distillation column and an aniline rectification column.
Primary distillation tower operating conditions: the temperature of the tower top is 100-135 ℃, the temperature of the tower bottom is 140-150 ℃, and the pressure of the tower top is 20-45 kPa (A); rectifying column operating conditions: the temperature of the tower top is 100-120 ℃, the temperature of the tower bottom is less than or equal to 115 ℃, and the pressure of the tower top is less than or equal to 15 kPa (A).
Example 1
And (3) starting a centrifugal pump I by a discharging valve I at the lower part of the aniline beating wastewater tank, opening an outlet valve II of the centrifugal pump, recovering crude aniline from the crude aniline tank, stopping recovery when the conductivity meter shows that the conductivity meter is 0.020s/m, and analyzing that the water content in the crude aniline tank is 1.81%.
Example 2
And (3) starting a centrifugal pump I by a discharging valve I at the lower part of the aniline beating wastewater tank, opening an outlet valve II of the centrifugal pump, recovering crude aniline from the crude aniline product tank, stopping recovery when the conductivity meter shows 0.012s/m, and analyzing that the water content in the crude aniline product tank is 0.98%.
Example 3
And (3) starting a centrifugal pump I by a discharging valve I at the lower part of the aniline beating wastewater tank, opening an outlet valve II of the centrifugal pump, recovering crude aniline from the crude aniline product tank, stopping recovery when the conductivity meter shows 0.008s/m, and analyzing that the water content in the crude aniline product tank is 0.76%.
Example 4
And starting a centrifugal pump I, opening an outlet valve II of the centrifugal pump, recovering crude aniline from the crude aniline product tank, stopping recovery when the conductivity meter shows 0.000s/m, and analyzing that the water content in the crude aniline product tank is 0.58%.
Comparative example 1
And (3) starting a centrifugal pump I, opening an outlet valve II of the centrifugal pump, recovering crude aniline from the crude aniline product tank, stopping recovery when the conductivity meter shows 0.230s/m, and analyzing that the water content in the crude aniline product tank is 3.58%.
Comparative example 2
And starting a centrifugal pump I, opening an outlet valve II of the centrifugal pump, feeding to the aniline primary distillation tower, and analyzing that the water content in the aniline crude product tank is 5.36%.
The implementation effects are shown in the following table:
| sequence number | Temperature at top of primary distillation column/DEGC | Pressure at top of primary distillation tower/kPa (A) | Low boiler content/% |
| Example 1 | 105.0~120.6 | 24~32 | 0.003240 |
| Example 2 | 106.3~118.6 | 26~31 | 0.003150 |
| Example 3 | 107.0~117.4 | 27~30 | 0.003010 |
| Example 4 | 107.5~114.0 | 28~29 | 0.002840 |
| Comparative example 1 | 95.8~130.9 | 32~53 | 0.005370 |
| Comparative example 2 | 94.4~133.4 | 30~58 | 0.006390 |
From the changes of the tower top temperature and pressure of the aniline primary distillation tower and the content of low-boiling-point substances in aniline, the lower the water content in crude aniline is, the more stable the crude distillation system is, and the lower the content of low-boiling-point substances in refined aniline is; the water content of the recovered aniline can be well controlled by the conductivity meter, and the purpose of continuously, stably and effectively recovering the aniline is realized.
Claims (7)
1. A method for continuously and stably recycling aniline in aniline wastewater is characterized in that an aniline wastewater flow automatic control device is arranged on an aniline wastewater recycling pipeline to control the water content of aniline in aniline crude products entering an aniline refining system, and the aniline crude products enter the aniline refining system to prepare aniline pure products; the aniline waste water flow control device comprises a centrifugal pump, an automatic regulating valve and a flowmeter, wherein a bypass of the automatic regulating valve is provided with a conductivity meter, and when the display value of the conductivity meter is greater than 0.02s/m, the automatic regulating valve is closed.
2. The method for continuously and stably recycling aniline in aniline wastewater according to claim 1, which is characterized by comprising an aniline wastewater tank, an aniline crude product tank and an aniline refining system, wherein an aniline wastewater flow automatic control device is arranged between the aniline wastewater tank and the aniline crude product tank.
3. The method for continuously and stably recycling aniline in aniline wastewater according to claim 1, wherein the flow range of the centrifugal pump is 0-10 m 3 /h。
4. The method for continuously and stably recycling aniline in aniline wastewater according to claim 1, wherein the water content of aniline in crude aniline product entering an aniline refining system is controlled to be less than 2.0%.
5. The method for continuously and stably recovering aniline from aniline wastewater according to claim 1, wherein the opening and closing of the automatic regulating valve is controlled by a conductivity meter.
6. The method for continuously and stably recovering aniline from aniline wastewater according to claim 1, wherein the aniline refining system comprises an aniline primary distillation column and an aniline rectification column.
7. The method for continuously and stably recovering aniline from aniline wastewater according to claim 6, wherein the primary distillation tower is operated under the following conditions: the temperature of the tower top is 100-135 ℃, the temperature of the tower bottom is 140-150 ℃, and the pressure of the tower top is 20-45 kPa (A); rectifying column operating conditions: the temperature of the tower top is 100-120 ℃, the temperature of the tower bottom is less than or equal to 115 ℃, and the pressure of the tower top is less than or equal to 15 kPa (A).
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1600696A (en) * | 2004-10-12 | 2005-03-30 | 南化集团研究院 | Nitrobenzene extraction method for treating aniline wastewater |
| CN102249376A (en) * | 2011-05-20 | 2011-11-23 | 北京化工大学 | Method for realizing recycling of aniline waste water and zero release through electropolymerization |
| CN102304017A (en) * | 2011-07-20 | 2012-01-04 | 济南圣泉集团股份有限公司 | Method for recycling aniline and methanol from mixed waste water of aniline and methanol |
| CN103641205A (en) * | 2013-10-29 | 2014-03-19 | 南京工业大学 | Dielectric barrier discharge-Fenton treatment combined technology for treating aniline wastewater |
| CN104610070A (en) * | 2015-02-11 | 2015-05-13 | 北海和思科技有限公司 | Combined method for performing dynamic adsorption and rectification on aniline in recycled wastewater |
| CN105906114A (en) * | 2016-07-05 | 2016-08-31 | 中国科学技术大学 | Bipolar membrane electrodialysis system for treating saliferous organic amine waste water by using carbon dioxide and process thereof |
-
2021
- 2021-04-29 CN CN202110473470.XA patent/CN113135827B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1600696A (en) * | 2004-10-12 | 2005-03-30 | 南化集团研究院 | Nitrobenzene extraction method for treating aniline wastewater |
| CN102249376A (en) * | 2011-05-20 | 2011-11-23 | 北京化工大学 | Method for realizing recycling of aniline waste water and zero release through electropolymerization |
| CN102304017A (en) * | 2011-07-20 | 2012-01-04 | 济南圣泉集团股份有限公司 | Method for recycling aniline and methanol from mixed waste water of aniline and methanol |
| CN103641205A (en) * | 2013-10-29 | 2014-03-19 | 南京工业大学 | Dielectric barrier discharge-Fenton treatment combined technology for treating aniline wastewater |
| CN104610070A (en) * | 2015-02-11 | 2015-05-13 | 北海和思科技有限公司 | Combined method for performing dynamic adsorption and rectification on aniline in recycled wastewater |
| CN105906114A (en) * | 2016-07-05 | 2016-08-31 | 中国科学技术大学 | Bipolar membrane electrodialysis system for treating saliferous organic amine waste water by using carbon dioxide and process thereof |
Non-Patent Citations (1)
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| 响应曲面法优化介质阻挡放电工艺处理苯胺废水;殷宝剑等;《净水技术》;20171231;摘要 * |
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